中等MATH-PROB-001
A fair six-faced die is rolled once. What is the probability that the result is a prime number?
A. 1/6
B. 1/2✓ 答案
C. 1/3
D. 2/3
解說
The prime faces are 2, 3 and 5, so the probability is 3/6 = 1/2. The number 1 is not prime. Counting only two primes gives 1/3.